Al-Zoabi said Turkey and Qatar bore "legal, moral and political responsibility" for the attack because of their support of rebel groups fighting to oust President Bashar Assad, Russia Today said.

Medical sources in Khan al-Assal said people suffering from suffocation and toxicity due to the exposure of unknown gases were being treated, China's Xinhua News Agency reported.

In other areas, including Idlib, Homs and Hamadiya, intense fighting between Syrian regime forces and rebel troops was reported. SANA said the army destroyed a number of terrorist hideouts and vehicles mounted with machine-guns.

Earlier in Istanbul, Turkey, Syria's main opposition group picked a naturalized U.S. citizen, Ghassan Hitto, 49, a Syrian-born telecommunications executive, as its first prime minister.

Some coalition members said the election would send a message to Assad the opposition could challenge his rule politically as well as militarily, The Wall Street Journal reported.

It was unclear how many rebel brigades would recognize the interim government as a legitimate authority, The New York Times said.

Hitto's election came hours after Syrian warplanes attacked suspected rebel hideouts across the border in eastern Lebanon, Lebanese and U.S. officials said.

The jet fighter and helicopter assault marked the first anti-rebel cross-border attack by the Assad regime since the Syrian conflict began two years ago, the Times said.

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